Safety trocar assembly

Safety trocar assembly device having:

• a portal unit with elongated, tubular cannula having an open distal end;
• a trocar unit having an elongated obturator adapted to be removably inserted through said cannula and having a penetrating end exposed through said open distal end of said cannula;
• a longitudinal central axis of grocer assembly;
• a penetrating means situated on said penetrating end of said obturator and having at least one penetrating zone with a cutting means that cuts the tissue in the cutting plane parallel to said longitudinal central axis, comprises at least one cutting edge having distal end and situated in said cutting plane;
• a displacement vector of said shield between its said extended and retracted position disposed in the plane parallel to said longitudinal axis of trocar assembly;
• said shield has proximal protected position, as such serves the extreme proximal position of said shield wherein said distal end of said cutting edge is protected,—said shield has screen area and as such serves that portion of said shield outer surface which, in said shield proximal protected position, is located outside said tubular cannula and protrudes beyond the bounds of members of said trocar assembly immovable relative to said tubular cannula during piercing the body tissue;
• said shield has a shield height and as such serves the distance from said shield outer surface to said cutting plane;
• said shield has a shield width and as such serves the distance from said shield outer surface to said longitudinal central axis;
• said shield is characterized by a local comparative height equal to the ratio of local maximal said shield height to local maximal said shield width measured in their common local plane perpendicular to said device longitudinal axis;
• said shield is low-profile shield having maximal said local comparative height that within the limits of said screen area is less than 0.5, therefore said shield is low profile shield and perimeter of the cross section of said shield insignificantly exceeds the perimeter of the tissue incision made by said cutting means thereby enabling said shield entry said incision without substantial resistance of the edges of said incision.